Abstract:

OBJECTIVE:  To observe the effects on T-lymphocyte subsets after different doses of irradiation. To investigate the cellular and molecular mechanisms of immune system injury induced by irradiation. METHODS：The C57BL/6j mice were divided into normal control group and model groups. The mice in radiation injury model were exposed to 60Co gamma rays (0.7, 1.4, 2.8 and 5.6 Gy). The surface markers and intracellular cytokines of lymphocytes were stained with fluorescence labeled monoclonal antibodies . The changes of T-lymphocyte subsets CD3+，CD4+，CD8+, IFN-r and interleukin-4 in spleen celles were analyzed by flow cytometry. RESULTS：T-lymphocyte subsets CD3+， CD4+，CD8+ were distinctly reduced after irradiation. This change was related to gamma ray doses. The CD4+/CD8+ was significantly increased. The Th1 and Th2 were depressed after irradiation and the decrement level of Th1 was larger than Th2. When irradiation dose was over 2.8 Gy, Th2/Th1 showed a marked increase compared with control group. CONCLUSION： Changes of mice T- lymphocyte subsets CD3+，CD4+，CD8+ and CD4+/CD8+ ratio could be caused by different doses of irradiation, especially the imbalance of Th1, Th2 and Th2/Th1 ratio that played an important role in radiation-induced immune injury.

Key words: radiation-induced immune injury, -lymphocyte subsets, h1, h2